Nrf51822 and STM32 uart bootloader problem

[Folny]

Hello

I try to use this bootloader https://github.com/williamhuang03/STM32F4-Custom-Bootloader on STM32F4 which works well through cable but as suddenly I use Nfr51 as transmitter and ESP32 as receiver so it doesn't work problem is that STM32 bootloader sends these commands in hex format #define ACK 0x06U, #define NACK 0x16U which Nrf51 uart rx ignores. Can mini advise where can be the problem ? I use the standard ble_app_uart code that is included with SDK_8.0.0 thank you for your advice.

[bjorn-spockeli]

Just to calrify: You have a STM32F sends UART commands to the nRF51 running the ble_app_uart example, which in turn sends these over BLE to a ESP32?

I think that the ble_app_uart example expects the '\n' character to be received before sending the string received over UART on BLE. 

Best regards

Bjørn 

[Folny]

Exactly, I tried to add an '\ n' update to the STM32 boot code, but I get an error while updating. I Have tested this modified code with FTDI usb and the update will succeed.

static void Send_ACK(UART_HandleTypeDef *handle)
{
    uint8_t msg[2] = {ACK, '\n'};
    
    HAL_UART_Tx(handle, msg, 2);
}

/*! \brief Sends an NACKnowledge byte to the host.
 *  
 *  \param  *UartHandle The UART handle
 */
static void Send_NACK(UART_HandleTypeDef *handle)
{
    uint8_t msg[2] = {NACK, '\n'};
    
    HAL_UART_Tx(handle, msg, 2);
}

[bjorn-spockeli]

I ran the first sentence through Google Translate, which returned " That's exactly what I tried to add '\ n' to the STM32 boot code, but I get an error". 

Ok, do you get an error on the STM side or the nRF51 side? Please elaborate.

[Folny]

Sorry I use Google translator :-) I think the error will definitely be on the Nrf51 wall because as I wrote through the cable everything works correctly I have already tried many options but the problem still persists.

[bjorn-spockeli]

Ok, can you run the ble_app_uart in a debug session and check wether the two bytes are being received or not, i.e. that you enter the UART event handler? You can alternatively output the received data using RTT. 

Best regards

Bjørn

[Folny]

I haven't tried the debug mode yet and I know very little about Nrf51 programming and I'm just learning and I'm hoping to come to this problem.

[bjorn-spockeli]

If you're using Keil to develop the nRF51 Firmware, then it should be fairly simple to debug the nRF51, see http://www2.keil.com/mdk5/debug. 

If you're using GCC with makefiles, then I would recommend using Segger Ozone, see Ozone The J-Link Debugger Introduction or GDB, see https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/using-gdb-with-nordic-devices.